The invention relates generally to an apparatus for monitoring the flexure angle between two jointed body limbs, for example, the knee flexure angle between a jointed thigh and lower portion of a human leg, as those limbs move in a vertical plane. In particular, the invention concerns a device useful for facilitating the monitoring of rehabilitative motions, such as knee bends.
Arthrometers measure joint motion. Generally, two types of arthrometers are currently available: passive arthrometers for measuring joint motion of another person, and automatic arthrometers for measuring one's own joint motion. Typically, passive arthrometers are referred to as goniometers.
The need to measure joint motion frequently occurs during rehabilitation therapy. For example, patients participating in post-operative therapy following knee surgery are often instructed to perform standing knee-bends from between, for example, 170 to 90 degrees. Similarly, after shoulder surgery, patients are often instructed to perform arm lifts over a predetermined range of motion in a vertical plane.
Prior art arthrometers are large, complex, and expensive. Large institutions can maintain such arthrometers, but once a patient is discharged from a health care facility, and such arthrometers are no longer available, the actual flexure angle of the patient's limbs are typically determined by mere guesswork.
Simple, automatic measurement of joint motion during exercise has not been heretofore available. Neither has there been available mechanisms for indicating actual range of motion and counting repetitions in an exercising cycle. Accordingly, individuals who have been discharged from a health care facility and instructed to maintain a therapeutic exercise regimen, have been faced with great difficulty in implementing that regimen.
It is therefore an object of the invention to provide a simple device for measuring joint motion which can be easily used by an unskilled operator. Another object of the invention is to provide such a device that is inexpensive, and does not interfere with the user's range of motion.